Information AboutBeaufort Scale |
|
The scale was created in 1806 by Sir Francis Beaufort , a British naval officer and Hydrographer . The initial scale from zero to 12 did not reference Wind Speed numbers, but related qualitative wind conditions to effects on a naval vessel, from "just sufficient to give steerage" to "that which no canvas {Link without Title} could withstand." The scale was made a standard for ship's log entries on Royal Navy vessels in the late 1830s. The scale was adapted to non-naval use from the 1850s, with scale numbers corresponding to cup Anemometer rotations. Rotations to scale numbers were standardised only in 1923. George Simpson , Director of the UK Meteorological Office , was responsible for this and for the addition of the land based descriptors. The measure was slightly altered some decades later to improve its utility for Meteorologist s. Wind speed on the Beaufort scale can be expressed by the formula: : ''v'' = 0.837 ''B''3/2 M/s where ''v'' is wind speed and ''B'' is Beaufort scale number. Today, Hurricane s are sometimes described as Beaufort scale 12 through 16, with the standard Saffir-Simpson Hurricane Scale Category 1 equivalent to Beaufort 12, Category 2 to Beaufort 13, and so on. Category 1 Tornado es on the Fujita and TORRO scales also begin at the end of level 12 of the Beaufort scale. Note that wave heights in the scale are for conditions in the open Ocean , not along shore. The scale is used in, and may be most recognizable to some from, the Shipping Forecast s broadcast on BBC Radio 4 in the United Kingdom . This scale is also widely used in China . Taiwan uses the Beaufort scale extended in 1944 with Forces 13-17 to better represent the wind caused by Typhoon s. Hong Kong and mainland China keep using Force 12 as the maximum. Macau adopted a set of simpler descriptions (calm, light, gentle, moderate, strong, gale, storm, hurricane) instead of the force numbers and descriptions in the table. In the United States , winds of Beaufort 6 or 7 result in the issuance of a Small Craft Advisory , with force 8 or 9 winds bringing about a Gale Warning , 10 or 11 a Storm Warning (or " Tropical Storm Warning " for 8 to 11 if related to a Tropical Cyclone ), and anything stronger a Hurricane Warning . REFERENCES
SEE ALSO EXTERNAL LINKS
|
|
|